The Hillside Akathisia Scale: a reliability comparison of the English and German versions.

Akathisia usually consists of two components, subjective restlessness and typical movements such as shuffling of the legs, pacing, shifting weight from one leg to the other, and rocking movements of the trunk. The ability to measure akathisia reliably is essential for the assessment of treatments for akathisia and for the evaluation of drug-induced side effects in general. To date, investigators have generally used self-constructed assessment scales without reporting data about reliability or validity. The Hillside Akathisia Scale (HAS) has two subjective and three objective items for which anchored rating points are provided. Reliability was 0.89 for the HAS total score. Reliability for rating subjective symptoms ranged from 0.86 to 0.92, and the objective scores ranged from 0.51 to 0.89. The correlation between HAS and a global assessment of akathisia (modified CGI) was 0.87. These values compare favorably with the original report on the scale indicating that the Hillside Akathisia Scale can validly quantify akathisia with a satisfactory degree of interrater reliability.